1. Field of the Invention
The invention relates to a touch module, and particularly relates to an optical touch module and a touch detecting method thereof.
2. Description of Related Art
Based on different sensing types, a touch panel can be generally categorized into a resistive touch panel, a capacitive touch panel, an optical touch panel, an acoustic-wave touch panel, and an electromagnetic touch panel. Since the touch mechanism of optical touch panels is suitable for large-sized display panels, the touch function of the large-sized display panels are mostly achieved by adopting the mechanism of optical touch control.
Referring to FIG. 1 below, FIG. 1 is a schematic view illustrating a structure of a conventional optical touch panel 1000. The optical touch panel 1000 includes an optical touch module 1200 and an optical touch plane 1400. In addition, the optical touch plane 1400 is formed in front of a display panel (i.e. the display panel is located at an inner side that is perpendicular to the drawing in FIG. 1) or on an electronic whiteboard. As shown in FIG. 1, the optical touch module 1200 is disposed at one side (e.g. upper side) of the optical touch plane 1400. The optical touch module 1200 includes light sensing components 1220 and 1240 and a computing unit 1260. The light sensing components 1220 and 1240 are commonly disposed near two corners of the optical touch plane 1400. By utilizing the shade due to a shielding effect or a light spot due to a reflection effect of the touch object OB on the optical touch plane 1400, the light sensing components 1220 and 1240 may respectively sense a touch object OB. Also, the computing unit 1260 may calculate the position of the touch object OB based on sensing results of the light sensing components 1220 and 1240.
In the optical touch panel 1000, the light sensing components 1220 and 1240 need to be disposed near two corners (e.g. the upper left and right corners) of the optical touch plane 1400 to sense the whole optical touch plane 1400. Generally speaking, a configuration of the optical touch module 1200 with respect to the optical touch plane 1400 may be categorized into an embedded type and an externally connected type. For the embedded type optical touch module 1200, the light sensing components 1220 and 1240 are embedded at two corners in the sidebars of the optical touch plane 1400. Therefore, the light sensing components 1220 and 1240 at different sensing angles need to be customized to be installed in the optical touch panels 1000 in different sizes. As for the externally connected type optical touch module 1200, the light sensing components 1220 and 1240 are integrated into a single module including a circuit board and a control unit, so as to be hung at one side (e.g. the upper side) of the optical touch panel 1400 matching the length of the module without specifically modifying the structure of the display panel or electronic whiteboard serving as the optical touch plane 1400. However, for the externally connected type optical touch module 1200, when the width of the optical touch plane 1400 shown in FIG. 1 (i.e. the length of the upper or lower side of the optical touch plane 1400) is changed, the distance between the optical sensing components 1220 and 1240 (i.e. the length of the optical touch module 1200) need to be changed accordingly. Therefore, when the optical touch planes 1400 in different sizes are provided, the length of the optical touch module 1200 needs to be changed as well. Otherwise, if a shorter optical touch module 1200 is used with a wider optical touch plane 1400, the touch object OB may not be effectively sensed and thus is unable to be positioned when the touch object OB is located at two sides of the optical touch plane 1400. Under such circumstance, parts (e.g. cables and/or cases of the touch module) made in different sizes are unfavorable for the control on parts and increase the difficulty and complexity in manufacture as well. Also, the large-sized optical touch module 1200 is not convenient to carry around.